Practical synthesis of an open geodesic polyarene with a fullerene-type 6:6-double bond at the center: diindeno[1,2,3,4-defg;1',2',3',4'-mnop]chrysene

Diindeno[1,2,3,4-defg;1',2',3',4'-mnop]chrysene (1), the smallest possible alkene-centered C60 substructure with a curved pi-system, is obtained in 25-35% yield by flash vacuum pyrolysis of the twisted 1,1'-dibromobifluorenylidene (2) on a 100 mg scale at 1050 degrees C. At 1200 degrees C, the bowl-shaped hydrocarbon 1 rearranges to the planar isomer diindeno[5,6,7,1-defg;5',6',7',1'-lmnop]chrysene (14) by a double 5/6 ring-expansion/ring-contraction. X-ray crystallography establishes that the central carbon atoms of 1 are nearly 80% as pyramidalized as the carbon atoms of C60 (POAV angles = 9.0 degrees and 11.6 degrees for 1 and C60, respectively). A four-step synthesis has been developed to prepare the pyrolysis precursor (2) as a mixture of (E)- and (Z)-isomers in 39% overall yield from commercially available 9-fluorenone-1-carboxylic acid (10).     

New galactolipids from the marine bacillariophycean microalga Nitzschia sp

Two new galactopyranosyldiacylglycerols have been isolated from the marine bacillariophycean microalga Nitzschia sp. and their structures were determined as (2S)-3-O-beta-D-galactopyranosyl-1,2-di-O-(9Z-hexadecenoyl)glycerol (1) and (2S)-3-O-beta-D-galactopyranosyl-1-O-(5Z,8Z,11Z,14Z,17Z-eicosapentaenoyl)-2-O-(9Z-hexadecenoyl)glycerol (2) by physicochemical evidence.     

STRUCTURE OF 3-CARBETHOXYPSORALEN PHOTOLYSIS PRODUCTS

Abstract— Upon UV-A irradiation(320–400 nm), the photorcaction of psoralens either with a solvent molecule or with a second psoralen molecule competes with the well-known photoaddition of psoralens to DNA. In the present study, a structural assignment of the 3-carbethoxypsoralen (3-CPs) photolysis products is proposed on the basis of their chromatographic (high performance liquid chromatography) and of their spectroscopic (absorption, fluorescence, mass spectrometry and ¹H Nuclear Magnetic Resonance) properties. Four photolysis products have been isolated and identified. The first one results from a water molecule addition on the 4',5' double bond of 3-CPs, the second from an ethanol molecule addition on the 4',5' double bond. Two cyclobutane type dimers of 3-CPs have also been characterized. These results confirm that, in protic solvents, the furan(4',5') double bond of 3-CPs is more photoreactive than the pyrone(3,4) double bond.     

传统中药甘遂根中二萜类化学成分的电喷雾质谱研究

应用电喷雾多级串联质谱技术对传统中药甘遂根中的弱极性部分化学成分进行了分析鉴定, 根据串联质谱数据, 共鉴定出39个化合物. 其中包括9个新化合物: 分别为3-O-(2,3-二甲基丁酰基)-13,20-O-双十二烷酰基巨大戟萜醇(1)、3-O-(2,3-二甲基丁酰基)-13-O-癸酰基-20-O-十六烷酰基巨大戟萜醇(2)、3-O-(2,3-二甲基丁酰基)-13-O-十二烷酰基-20-O-[(9Z,12Z)-十八烷-9,12-二烯酰基]巨大戟萜醇(3)、3-O-(2,3-二甲基丁酰基)-13-O-十二烷酰基-20-O-(十八烷-9Z-烯酰基)巨大戟萜醇(4)、甘遂素I(5)、甘遂素J(6)、甘遂素K(7)、甘遂素L(8)和甘遂素M(9).     

Three new flavonoid glycosides, byzantionoside B 6'-O-sulfate and xyloglucoside of (Z)-hex-3-en-1-ol from Ruellia patula

Three new flavonoid glycosides, demethoxycentaureidin 7-O-β-D-galacturonopyranoside, pectolinarigenin 7-O-α-L-rhamnopyranosyl-(1?→4″)-β-D-glucopyranoside and 7-O-α-L-rhamnopyranosyl-(1?→4″)-β-D-glucuronopyranoside, a new megastigmane glucoside, byzantionoside B 6'-O-sulfate, and a new (Z)-hex-3-en-1-ol O-β-D-xylopyranosyl-(1″→2')-β-D-glucopyranoside, were isolated from leaves of Ruellia patula JACQ., together with 12 known compounds, β-sitosterol glucoside, vanilloside, bioside (decaffeoyl verbascoside), acteoside (verbascoside), syringin, benzyl alcohol O-β-D-xylopyranosyl-(1″→2')-β-D-glucopyranoside, cistanoside E, roseoside, phenethyl alcohol O-β-D-xylopyranosyl-(1″→2')-β-D-glucopyranoside, (+)-lyoniresinol 3α-O-β-D-glucopyranoside, isoacteoside and 3,4,5-trimethoxyphenol O-α-L-rhamnopyranosyl-(1″→6')-β-D-glucopyranoside. Their structures were elucidated by means of spectroscopic analyses.     

Carboracycles: Macrocyclic Compounds Composed of Carborane Icosahedra Linked by Organic Bridging Groups

A family of macrocyclic compounds are described, together with their precursors. These cycles are composed of icosahedral carboranes linked via their carbon vertices through 1,3-trimethylene, alpha,alpha'-1,3-xylylene, or alpha,alpha'-2,6-lutidylene groups. The compounds cyclo-(1,3-trimethylene-1',2'-closo-1',2'-C(2)B(10)H(10))(4) (6a), cyclo-(1,3-trimethylene-1',2'-closo-9',12'-dimethyl-1',2'-C(2)B(10)H(8))(4) (6b), cyclo-(1,3-trimethylene-1',2'-closo-1',2'-C(2)B(10)H(10))(3) (9), cyclo-(alpha,alpha'-1,3-xylylene-1',2'-closo-1',2'-C(2)B(10)H(10))(2) (11a), cyclo-(alpha,alpha'-1,3-xylylene-1',7'-closo-1',7'-C(2)B(10)H(10))(2) (11b), cyclo-(alpha,alpha'-1,3-xylylene-1',7'-closo-9',10'-dimethyl-1,7-C(2)B(10)H(8))(2) (11c), cyclo-(alpha,alpha'-1,3-xylylene-1',2'-closo-1',2'-C(2)B(10)H(10))(4) (12), cyclo-(alpha,alpha'-1,3-xylylene-1',7'-closo-1',7'-C(2)B(10)H(10))(3) (13), cyclo-(alpha,alpha'-2,6-lutidylene-1',7'-closo-1',7'-C(2)B(10)H(10))(2) (19), and cyclo-(alpha,alpha'-2,6-lutidylene N-oxide-1',7'-closo-1',7'-C(2)B(10)H(10))(2) (20) have been synthesized. The structures of 6a, 6b, 9, 11a, 11b, 11c, 12, and 19 have been determined by X-ray crystallography. Crystal data: for 6a, triclinic, space group P&onemacr;, a = 11.131(2) ?, b = 12.642(2) ?, c = 12.996(2) ?, alpha = 84.383(6) degrees, beta = 65.884(6) degrees, gamma = 97.292(5) degrees, Z = 1, R = 0.079; for 6b, monoclinic, space group P2(1)/a, a = 13.500(2) ?, b = 31.141(3) ?, c = 13.831(2) ?, beta = 99.90(1) degrees, Z = 2, R = 0.097; for 11a, monoclinic, space group C2/c, a = 14.5682(8) ?, b = 14.5046(8) ?, c = 16.1998(8) ?, beta = 95.631(2) degrees, Z = 4, R = 0.081; for 11b, monoclinic, space group P2(1)/n, a = 11.650(2) ?, b = 10.606(2) ?, c = 11.730(2) ?, beta = 104.951(6) degrees, Z = 2, R = 0.069; for 11c, orthorhombic, space group Pbca, a = 12.532(2) ?, b = 14.271(2) ?, c = 18.143(3) ?, Z = 4, R = 0.076; for 19, orthorhombic, space group Pcab (No. 61, standard setting Pbca), a = 11.0428(6) ?, b = 11.3785(6) ?, c = 22.533(1) ?, Z = 4, R = 0.074.     

Inhibitory effects of constituents from Euphorbia lunulata on differentiation of 3T3-L1 cells and nitric oxide production in RAW264.7 cells

A new flavonol galactopyranoside, myricetin 3-O-(2',3'-digalloyl)-β-D-galactopyranoide (1), and 23 known constituents, including myricetin 3-O-(2'-galloyl)-β-D-galactopyranoide (2), myricitrin (3), myricetin (4), quercetin 3-O-(2', 3'-digalloyl)-β-D-galactopyranoide (5), quercetin 3-O-(2'-galloyl)-β-D-galactopyranoide (6), hyperin (7), isoquercetrin (8), quercetin (9), kaempferol (10), apigenin (11), luteolin (12), 3-O-methylquercetin (13), 5,7,2',5'-tetrahydroxyflavone (14), 1,3,4,6-tetra-O-galloyl-β-D-glucose (15), 1,2,6-tri-O-galloyl-β-D-glucose (16), 1,3,6-tri-O-galloyl-β-D-glucose (17), gallic acid (18), protocatechuic acid (19), 3,4,5-trimethoxybenzoic acid (20), 2,6-dihydroxyacetophenone (21), 3,3'-di-O-methylellagic acid (22), ellagic acid (23) and esculetin (24) were isolated from Euphorbia lunulata Bge. Their structures were determined by spectroscopic analysis. Isolated hydrolysable tannins, flavonoids, and flavonol galactopyranoside gallates showed significant inhibition of the differentiation of 3T3-L1 preadipocytes and triglyceride accumulation in maturing adipocytes, and nitric oxide production in RAW 264.7 cells.     

2’，4”-O-双(三甲基硅)-6-O-甲基红霉素A 9-O-(1-甲氧基环己基)肟的区域选择性合成机理及其晶体结构

合成了化合物3的6-OH区域选择性甲基化产物, 即2',4"-O-双(三甲基硅)-6-O-甲基红霉素A 9-O-(1-甲氧基环己基)肟(4)的单晶, 以及化合物2的单晶, 并确定了其立体构型, 以期阐明区域选择性与大环内酯构象之间的关系.     

Bioconversion of 7-Hydroxyflavanone: Isolation, Characterization and Bioactivity Evaluation of Twenty-One Phase I and Phase II Microbial Metabolites

Microbial metabolism of 7-hydroxyflavanone (1) with fungal culture Cunninghamella blakesleeana (ATCC 8688a), yielded flavanone 7-sulfate (2), 7,4'-dihydroxyflavanone (3), 6,7-dihydroxyflavanone (4), 6-hydroxyflavanone 7-sulfate (5), and 7-hydroxyflavanone 6-sulfate (6). Mortierella zonata (ATCC 13309) also transformed 1 to metabolites 2 and 3 as well as 4'-hydroxyflavanone 7-sulfate (7), flavan-4-cis-ol 7-sulfate (8), 2',4'-dihydroxychalcone (9), 7,8-dihydroxyflavanone (10), 8-hydroxyflavanone 7-sulfate (11), and 8-methoxy-7-hydroxyflavanone (12). Beauveria bassiana (ATCC 7159) metabolized 1 to 2, 3, and 8, flavanone 7-O-β-D-O-4-methoxyglucopyranoside (13), and 8-hydroxyflavanone 7-O-β-D-O-4-methoxyglucopyranoside (14). Chaetomium cochlioides (ATCC 10195) also transformed 1 to 2, 3, 9, together with 7-hydroxy-4-cis-ol (15). Mucor ramannianus (ATCC 9628) metabolized 1 in addition to 7, to also 4,2',4'-trihydroxychalcone (16), 7,3',4'-trihydroxyflavanone (17), 4'-hydroxyflavanone 7-O-α-L-rhamnopyranoside (18), and 7,3',4'-trihydroxy-6-methoxyflavanone (19). The organism Aspergillus alliaceus (ATCC 10060) transformed 1 to metabolites 3, 16, 7,8,4'-trihydroxyflavanone (20), and 7-hydroxyflavanone 4'-sulfate (21). A metabolite of 1, flavanone 7-O-β-D-O-glucopyranoside (22) was produced by Rhizopus oryzae (ATCC 11145). Structures of the metabolic products were elucidated by means of spectroscopic data. None of the metabolites tested showed antibacterial, antifungal and antimalarial activities against selected organisms. Metabolites 4 and 16 showed weak antileishmanial activity.     

New phenolic constituents from the fruit juice of Phyllanthus emblica

Six new phenolic constituents, L-malic acid 2-O- (1), mucic acid 2-O- (5), mucic acid 1,4-lactone 2-O- (6), 5-O- (8), 3-O- (10), and 3,5-di-O- (11) gallates, were isolated from the fruit juice of Phyllanthus emblica together with their methyl esters (2-4, 7, 9), and their structures were determined by spectral and chemical methods. Compounds 5, 6, and 8, the major phenolic constituents of the juice, were present as an equilibrium mixture in aqueous solution.     

Four new phenones from the cortexes of Polygala tenuifolia

From the 95% EtOH extract of the cortexes of Polygala tenuifolia, four new phenones and three known xanthones were isolated. The structures of the four new phenones were identified as 4-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl]-2-hydroxyl-6-methoxybenzophenone (tenuiphenone A, 1), 3,5-di-C-beta-glucopyranosyl-2,4,6,3'-tetrahydroxybenzophenone (tenuiphenone B, 2), 2',4',6'-trihydroxyphenyl-(24Z)-triacontene-1-one (tenuiphenone C, 3), 2',4',6'-trihydroxyphenyl-(26Z)-dotriacontene-1-one (tenuiphenone D, 4) respectively, on the basis of spectroscopic analyses. The isolation of 1 and 2 supplied an evidence for the hypothesis that xanthone was biosynthesized from benzophenone in the plants.     

Syntheses and structural characterization of the (OCnOPor) capped porphyrins: Co(OC2OPor).CH2Cl2, Co(OC2OPor)(NO)out.0.46CHCl3, Co(OC3OPor).CHCl3, and Co(OC3OPor)(MeIm).3C7H8

The compounds Co(OC2OPor).CH2Cl2 (1), Co(OC2OPor)(NO)out.0.46CHCl3 (2), Co(OC3OPor).CHCl3 (3), and Co(OC3OPor)(MeIm).3C7H8 (4) (OC2OPor = 5,10,15,20-(benzene-1,2,4,5- tetrakis(2-phenyloxy)ethoxy)-2',2",2"',2"-tetraylporphyrinato dianion; OC3OPor = 5,10,15,20-(benzene-1,2,4,5-tetrakis(2- phenyloxy)propoxy)-2',2",2"',2"-tetraylporphyrinato dianion; MeIm = 1-methylimidazole), have been synthesized, and their structures have been determined by single-crystal X-ray diffraction methods at T = -120 degrees C: 1, a = 8.824(1) A, b = 16.674(1) A, c = 16.836(1) A, alpha = 104.453(1) degrees, beta = 92.752(1) degrees, gamma = 90.983(1) degrees, P1, Z = 2; 2, a = 9.019(1) A, b = 16.588(2) A, c = 16.909(2) A, alpha = 103.923(2) degrees, beta = 92.082(2) degrees, gamma = 93.583(2) degrees, P1, Z = 2; 3, a = 13.484(3) A, b = 14.404(3) A, c = 14.570(3) A, alpha = 105.508(3) degrees, beta = 100.678(3) degrees, gamma = 93.509(4) degrees, P1, Z = 2; 4, a = 16.490(1) A, b = 22.324(2) A, c = 17.257(1) A, b = 92.437(1) degrees, P2(1)/n, Z = 4. These compounds are the first structurally characterized Co-bound members of the OCnOPor ligand system. The NO ligand in 2 and the MeIm ligand in 4 bind asymmetrically and lead to several metrical changes in these porphyrins, e.g., variations in average porphyrin deviations and Co atom displacements relative to the porphyrinato N atoms and the mean porphyrin planes.     

Chemical constituents of Melicope ptelefolia

Phytochemical investigations on the methanolic extract of Melicope ptelefolia Champ ex Benth. resulted in the isolation of three new compounds, identified as 3beta-stigmast-5-en-3-ol butyl tridecanedioate (melicoester) (1), (2Z, 6Z, 10Z, 14Z, 18Z, 22Z, 26E)-3', 7', 11', 15', 19', 23', 27', 31'-octamethyldotriaconta-2, 6, 10, 14, 18, 22, 26, 30-octadecanoate (melicopeprenoate) (2) and p-O-geranyl-7"-acetoxy coumaric acid (3). The compounds were isolated along with twenty-one other known compounds, lupeol (4), oleanolic acid (5), kokusaginine (6) genistein (7), p-O-geranyl coumaric acid (8), 4-stigmasten-3-one (9), 3beta-hydroxystigma-5-en-7-one (10) cis-phytyl palmitate (11), dodecane, dodecan-1-ol, ceryl alcohol, hentriacontanoic acid, eicosane, n-amyl alcohol, caprylic alcohol, octatriacontane, nonatriacontane, hexatriencontan-1-ol, methyl octacosanoate, beta-sitosterol, beta-sitosterol glucoside. Structures of all the compounds were established on the basis of MS and 1D and 2D NMR spectral data, as well as comparison with reported data.     

Novel formation of iodobenzene derivatives from 1-(methylthio)-3-tosylhexa-1,3-dien-5-ynes via iodine-induced intramolecular cyclization

The reaction of (1E,3E)-1-(methylthio)-3-tosylhexa-1,3-dien-5-ynes (3) with iodine to form iodine-substituted benzenes (4) is reported. The reaction of 3 with iodine proceeded very slowly, but UV irradiation accelerates the reaction to give 4 in high-to-excellent yields. Irradiation induces the cis-trans isomerization of the C1-C2 double bond, leading to the (1Z,3E)-geometric isomer (3'), which easily reacts with iodine to afford 4. This reaction is applicable to 3-(methoxycarbonyl)-1-(methylthio)-6-phenylhexa-1,3-dien-5-yne (11), which is synthesized as a geometric mixture. Interestingly, this mixture can be used as the starting material. Irradiation of the mixture (the geometric isomer ratio = 50:28:5:17) with iodine resulted in the formation of methyl 3-iodo-4-phenylbenzoate (12) in 80% yield.     

Cyclam kappa4 to kappa3 ligand denticity change upon mono-n-substitution with a carboxypropyl pendant arm in a ruthenium nitrosyl complex

The complex fac-[Ru(NO)Cl2(kappa(3)N(4),N(8),N(11)(1-carboxypropyl)cyclam)]Cl.H2O (1-carboxypropyl)cyclam=3-(1,4,8,11-tetraazacyclotetradecan-1-yl)propionic acid) was prepared in a one pot reaction by mixing equimolar amounts of RuNOCl 3 and (1-carboxypropyl)cyclam and was characterized by X-ray crystallography, electrospray ionization tandem mass spectrometry (ESI-MS/MS), elemental analysis, NMR, and electronic and vibrational (IR) spectroscopies. fac-[Ru(NO)Cl 2(kappa(3)N(4),N(8),N(11)(1-carboxypropyl)cyclam)]Cl.H2O crystallizes in the triclinic, space group P1, No. 2, with unit cell parameters of a=8.501(1) A, b=9.157(1) A, c=14.200(1) A, alpha=72.564(5) degrees , beta=82.512(5) degrees , gamma=80.308(5) degrees , and Z=2. The Ru-N interatomic distance and bond angle in the [Ru-NO] unit are 1.739(2) A and 167.7(2) degrees , respectively. ESI-MS/MS shows characteristic dissociation chemistry that initiates by HCl or NO loss. The IR spectrum displays a nu(NO) at 1881 cm(-1) indicating a nitrosonium character. The electronic spectrum shows absorptions bands at 264 nm (log epsilon=3.27), 404 nm (log epsilon=2.53), and 532 nm (log epsilon=1.88). (1)H and (13)C NMR are in agreement with the proposed molecular structure, which shows a very singular architecture where the cyclam ring N (with the carboxypropyl pendant arm) is not coordinated to the ruthenium resulting in a kappa(3) instead of the expected kappa(4) denticity.     

Coordination chemistry of a novel tetramacrocyclic ligand derived from 1,4,7-triazacyclononane: synthesis,structure, and properties of nickel(II) and copper(II) complexes

A new polynucleating ligand, 1,2,4,5-tetrakis(1,4,7-triazacyclonon-1-ylmethyl)benzene (Ldur), has been prepared and characterized as its dodecahydrobromide salt. Addition of base to an aqueous solution of this salt and 4 molar equivalents (m.e.) of a Ni(II) salt produces a mixture of bi- and trinuclear complexes, which can be separated by cation-exchange chromatography (CEC) and crystallized as [Ni2Ldur](ClO4)(4).2H2O (1) and [Ni3Ldur(H2O)6](ClO4)(6).9H2O (2). The "full capacity" tetranuclear complex, [Ni4Ldur(H2O)12](ClO4)(8).8H2O (3), is obtained by slow addition of Ldur to a refluxing aqueous solution of excess Ni2+ ions, followed by CEC purification. Treatment of Ldur with 4 m.e. of a copper(II) salt produces exclusively the tetranuclear complex, [Cu4Ldur(H2O)8](ClO4)(8).9H2O (4), while reaction with only 2 m.e. of Cu2+ ions yields the binuclear complex, [Cu2Ldur](ClO4)(4).4H2O (5). The X-ray structures of complexes 1,2,4, and [Cu2Ldur](ClO4)(4).3H2O (5') have been determined; all are monoclinic, P2(1)/c: for 1, a = 9.497(3) A, b = 13.665(5) A, c = 19.355(6) A, beta = 100.57(2) degrees, V = 2469(1) A3, and Z = 2; for 2, a = 22.883(7) A, b = 15.131(6) A, c = 20.298(8) A, beta = 97.20(3) degrees, V = 6973(4) A3, and Z = 4; for 4, a = 16.713(7) A, b = 16.714(6) A, c = 14.775(11) A, beta = 108.24(5) degrees, V = 3920(4) A3, and Z = 2; and for 5', a = 9.5705(1) A, b = 13.0646(1) A, c = 20.1298(2) A, beta = 103.1618(8) degrees, V = 2450.81(4) A3, and Z = 2. The metal centers in 1 and 5' lie in distorted octahedral environments, each facially coordinated by two of the triamine rings of Ldur, the cation in each case being centrosymmetric. In 2, one of the nickel(II) centers is similarly sandwiched by two triamine rings, while the other two nickel(II) centers are each coordinated by a single triamine ring from the ligand, with their distorted octahedral coordination spheres each being completed by three water molecules. In 4, the four triamine rings of Ldur bind to separate copper(II) centers, with two water molecules occupying the remaining two sites of the distorted square pyramidal (SP) coordination spheres, the cation again being centrosymmetric.     

[Cu(NBUOCTB)](ClO~4)~2.2DMF的晶体结构和热分解反应动力学

本文制备了二(N,N-二甲基甲酰胺)合高氯酸N,N,N',N"-四[(1'-正丁基-2'-苯并咪唑)甲基]-1,2-环己二胺合铜(Ⅱ), [Cu(NBUOCTB)](ClO~4)~2.2DMF。测定表明其晶体属正交晶系, 空间群为Pban, a=1.2553(2), b=2.0022(8),c=2.5687(5)nm, V=6.456(4)nm^3, Mr=1267.84, Z=4, Dx=1.304g/cm^3,μ=4.81cm^-^1, F(000)=2684。利用TG-DTG技术研究了配合物的热分解过程。采用积分法和微分法相结合方案, 对实验数据进行分析。推断第一步热分解过程为成核和生长机理(n=1), 符合Avrami-Erofeev方程; 第二步热分解过程为二级化学反应机理。     

Overcrowded 1,8-diazafluorenylidene-chalcoxanthenes. Introducing nitrogens at the fjord regions of bistricyclic aromatic enes

The effects of introducing nitrogen atoms in the fjord regions and chalcogen bridges on the conformations of overcrowded bistricyclic aromatic enes (1, X not equal to Y) (BAEs) were studied. 9-(9'H-1',8'-Diazafluoren-9'-ylidene)-9H-thioxanthene (12), 9-(9H-1',8'-diazafluoren-9'-ylidene)-9H-selenoxanthene (13), 9-(9'H-1',8'-diazafluoren-9'-ylidene)-9H-telluroxanthene (14), 9-(9' H-1',8'-fluoren-9-ylidene)-9H-xanthene (15) and 9-(9' H-1',8'-fluoren-9'-ylidene)-9H-fluorene (16) were synthesized by two-fold extrusion coupling reactions of 1,8-diaza-9H-fluoren-9-one (19)/chalcoxanthenthiones (24-27) (or /9H-fluorene-9-thione (30)). The 1',8'-diazafluoren-9-ylidene-chalcoxanthenes (11) were compared with the respective fluoren-9-ylidene-chalcoxanthenes (10). The structures of 12-16 were established by 1H, 13C, 77Se, and 125Te NMR spectroscopies. The crystal and molecular structures of 12-14 were determined by X-ray analysis. The yellow molecules of 12-14 adopted mono-folded conformations with folding dihedrals in the chalocoxanthylidene moieties of 62.7 degrees (12), 62.4 degrees (13) and 59.9 degrees (14). The folding dihedrals in the respective 1',8'-diazafluorenylidene moieties were very small, ca. 2 degrees, compared with 10.2/8.0 degrees in (9'H-fluoren-9'-ylidene)-9H-selenoxanthene (7). A 5 degree pure twist of C9=C9' in 14 is noted. The degrees of overcrowding in the fjord regions of 12-14 (intramolecular non-bonding distances) were relatively small. The degrees of pyramidalization of C9 and C9' were 17.0/3.0 degrees (12), 17.4/2.4 degrees (13) and 2.2/2.2 degrees (14). These high values in 12 and 13 stem from the resistance of the 1.8-diazafluorenylidene moiety to fold and from the limits in the degrees of folding of the thioxanthylidene and selenoxanthylidene moieties (due to shorter S10-C4a/S10-C10a and Se10-C4a/Se10-C10a bonds, as compared with the respective Te-C bonds in 14). The molecules of 15 and 16 adopt twisted conformations, a conclusion drawn from the 1H NMR chemical shifts of the fjord regions protons (H1 and H8) at 8.70 (15) and 9.00 ppm (16) and from their colors and UV/VIS spectra: 15 is purple (lambdamax = 521 nm) and 16 is orange-red. A comparison of the NMR spectra of 11 and 10 (deltadelta = delta(11) -delta(10)) showed substantial downfield shifts of 0.56-0.62 ppm of the fjord regions protons of twisted 15 and 16: deltadelta (C9) were negative (upfield): -4.0 (12), -3.7 (13), -3.4 (14), -7.1 (15), -5.0 ppm (16), while deltadelta (C9') were positive (downfield) = +6.8 (12), +6.5 (13), +5.8 (14), + 11.7 (15), +7.7 ppm (16). In 15, deltadelta (C9) - deltadelta (C9') = + 18.8 ppm, attributed to a push-pull character and significant contributions of zwitterionic structures in the twisted conformation. The 77Se and 125Te NMR signals of 13 and 14 were shifted upfield relative to the respective fluorenylidene-chalcoxanthene derivatives: deltadelta77Se = 17.2 ppm and deltadelta125Te = 22.0 ppm. The presence of the nitrogen atoms (N1' and N8') in 13 and 14 causes shielding of the selenium and tellurium nuclei.     

Proton-sensitive fluorescent organogels

A 1,10-phenanthroline-appended cholesterol-based gelator (1) and its nongelling reference compound (2) were synthesized. Among 19 solvents tested herein, gelator 1 could gelate 11 solvents including alcohols, dipolar aprotic solvents, organic acids and a base (triethylamine), indicating that 1 acts as a versatile gelator. The TEM observation gave a visual image showing that fibrillar aggregates are entangled in the three-dimensional network structure. In the fluorescence measurements, most gels afforded an emission maximum at 394 nm (purple emission), whereas only the acetic acid gel afforded an emission maximum at 522 nm (yellow emission). Thus, the influence of protonation of the 1,10-phenanthroline nitrogens (by trifluoroacetic acid) on the fluorescence properties in the gel phase was investigated in detail. The results have established that the fluorescence intensity of 1 x H+ becomes particularly strong in the gel phase, presumably because of the energy transfer from neutral 1* to protonated 1 x H+ and the restriction of the 1 x H+ molecular motion. The finding suggests the possibility that the gel system would be useful not only as a new proton-sensitive fluorescence system but also as a new medium for designing efficient energy transfer systems.     

Adduct of acetylene at sulfur in an oxygen- and sulfur-bridged open cubane cluster complex of tungsten

Formation of a single carbon-sulfur bond is described. The reaction of incomplete cubane-type sulfur and oxygen-bridged isothiocyanato tungsten cluster [W3(mu3-S)(mu-O)(mu-S)2(NCS)9]5- (7) with acetylene affords [W3(mu3-S)(mu-O)(mu-S)(mu-SCH=CH2)(NCS)9]4- (8). The cluster 8 has been isolated as K0.5(Hpy)3.5[W3(mu3-S)(mu-O)(mu-S)(mu-SCH=CH2)(NCS)9] (8'), whose structure has been characterized by X-ray crystallography, electronic spectra, and 1H and 13C NMR spectroscopy. Crystal data of 8': triclinic system, space group P1, a = 14.465(5) A, b = 17.353(3) A, c = 10.202(2) A, alpha = 90.98(1) degrees, beta = 108.59(2) degrees, gamma = 98.13(2) degrees, V = 2397.6(10) A(3), Z = 2, D(c) = 2.096 g cm(-3), Dm = 2.08 g cm(-3), R (Rw) = 3.6 (5.5)% for 8786 reflections (I > 1.50 sigma(I)). The carbon-carbon distance is 1.27(1) A and is almost equidistant between ethylene (1.339 A) and acetylene (1.203 A). The electronic spectrum of 8' in 1.0 M HCl containing 1.5 M KSCN has a characteristic broad peak in the near-infrared region [lambda(max), nm (epsilon, M(-1) cm(-1)): 840 (650), 575 (1450)]. (1)H NMR and HH correlation spectroscopy (COSY) of 8' in CD3CN support the results of the X-ray structural analysis. The (1)H NMR spectrum shows three signals at 2.42 (1H, dd), 4.84 (1H, d, J = 8.8 Hz), and 4.89 (1H, d, J = 16.2 Hz) ppm due to the mu-SCH=CH2 moiety of 8'. The correlation spectrum shows spin couplings of the signal at 2.42 ppm with the signals at 4.84 and 4.89 ppm. The mechanism of the formation of 8 is suggested to proceed through an intermediate with acetylene bridging two of the sulfur atoms.